Devices for mixing gases with liquids are known. In the typical mixing device, or ejector as they sometimes may be called, a flowing stream of fluid passing through a chamber between an orifice and a throat creates a vacuum which draws a gas from its source and mixes the same with the fluid flowing through the chamber. Such devices are used to mix gaseous chlorine with water in water treatment plants.
It has been found that when chlorine gas is mixed with water from certain sources, trihalomethanes can be formed. Trihalomethanes are suspected to be carcinogenic. Heretofore, the formation of trihalomethanes has been controlled by adding ammonia to the water to form amines, and thereafter adding chlorine. The chlorine combines with the amines to form chloramines which are not suspected to be carcinogenic.
Certain problems have been encountered in mixing ammonia with water in ejectors. For instance, when ammonia is mixed with water containing high proportions of certain minerals, such as calcium carbonate, solid precipitates tend to form in the throat, and this requires periodic cleaning of the ejector with concomitant downtime of the water treatment unit. Water softeners have been used to demineralize the water before it flows through the ejector and mixes with the ammonia. However, a major disadvantage of using softened water is in the initial cost to install the softening equipment and the cost to maintain the same.